Having started to compile a new rig, makes you want clear skies to photograph, and yesterday provided the clear skies wanted. I went out to test my new Sky Watcher Star Adventurer GTi, after balancing and polar aligning the mount I managed to observe three different objects. Firstly I had my first go at focusing my camera with a Bathinov mask, something I have never tried before.
After focusing I tested a few shots of M45 Pleiades
I realize that there is a problem with a slight elongation of the stars in the image. The reason for this is that I have a UV filter that is stuck at the front end of my Tamron 150-600mm lens. This causes the light to travel slightly differently through the lens causing this elongation of the stars.
How do I know that this does not originate from alignment errors? Well, the elongation of the stars is the same no matter if the exposure time is 1/125″ or 30″.
Furthermore, the problem is seen at any point in the sky. The photos has been stacked in Deep Sky Stacker and edited in Photoshop afterwards.
M45 – Facts
The Pleiades also known as the seven sisters is an open star cluster with middle-aged, hot B-type stars. The cluster is located in the northwestern part of the constellation of Taurus. The distance to M45 is approximately 444 lightyears from the Solar system, making this cluster one of the nearest star clusters.
The apparent magnitude of M45 is 1.6 in the V-band.